Tunneling-induced broadband and tunable optical emission from plasmonic nanorod metamaterials

We demonstrate a metamaterial platform for electrically driven broadband light emission induced by electron tunneling. Both the Fabry-Perot and waveguided modes of the metamaterial slab as well the plasmonic mode of the tunneling gap are identified as contributing to shaping the emission spectrum. This opens up an opportunity to design the spectrum and polarization of the emitted light by tuning the metamaterial modes via the geometric parameters of the nanostructure throughout the visible and near-infrared spectral ranges. The efficient coupling of the tunneling-induced emission to the waveguided modes is beneficial for the development of integrated incoherent light sources, while the outcoupled emission provides a source of free-space radiation. The demonstrated incoherent nanoscale light sources may find applications in the development of integrated opto-electronic circuits, optical sensing platforms, imaging, and metrology.